A wrinkle in time: Finding the ice age in urban Los Angeles

Just beyond the traffic and palm trees of Wilshire Boulevard, hidden beneath the shadows of nondescript office buildings, lie the tar-slicked bones of many thousand long-dead creatures.

These unfortunates found themselves mired in the sticky bitumen of La Brea’s tar pits tens of thousands of years ago during the last glacial period. They have remained there ever since, providing scientists with an unrivaled window into the past, even as the city of Los Angeles materialized around t...